1. Field of the Invention
The present invention is related to: a solid-state image capturing apparatus; a method for manufacturing the solid-state image capturing apparatus; and an electronic information device, and more specifically, a solid-state image capturing apparatus including light-receiving sections each constituted of an embedded photodiode and capable of reading out a signal charge from the light-receiving section in low voltage drive and realizing low-noise and high-definition images, a method for manufacturing the solid-state image capturing apparatus, and an electronic information device including the solid-state image capturing apparatus.
2. Description of the Related Art
Conventionally, a solid-state image capturing apparatus includes a CCD solid-state image capturing apparatus and a CMOS solid-state image capturing apparatus. For example, Reference 1 discloses a conventional CCD solid-state image capturing apparatus.
FIG. 11 is a schematic view of the solid-state image capturing apparatus disclosed in Reference 1.
A conventional solid-state image capturing apparatus 200 shown in FIG. 11 includes: an n-type impurity diffusion layer 5, which forms a sensor region (light-receiving section) on a substrate 1 such as a wafer; a p-type impurity diffusion layer 7, which forms a transfer channel region (charge transferring section) for transferring a signal charge generated in the light-receiving section; and a p-type impurity diffusion layer 30 (hereinafter, also referred to as “diffusion layer 30”), which forms a readout gate region (ROG) for reading out the signal charge generated in the light-receiving section to the transfer channel region. In addition, in the solid-state image capturing apparatus 200 a transfer electrode 19, including an opening 19a at a section corresponding to the sensor region, is formed on the substrate 1 with a gate insulation layer 18 interposed therebetween.
The diffusion layer 7 of the transfer channel region, the impurity diffusion layer 5 of the sensor region, and impurity diffusion layer 30 of the readout gate region, are formed prior to the formation of the transfer electrode 19. A p-type diffusion layer 9 in a surface portion of the sensor region is formed by ion implantation via the opening 19a of the electrode 19.
In the solid-state image capturing apparatus 200 shown in FIG. 11, prior to the formation of an n-type epitaxial layer 2 of the substrate 1, a carbon implantation region 34 is formed for reducing dark current or white defects. In addition, the n-type silicon epitaxial layer 2 is formed above the substrate 1, and a p-type semiconductor well region 4 is formed within the epitaxial layer 2. Further, within the p-type semiconductor well region 4, the diffusion layer 7 of the transfer channel region, an n-type channel stop layer 8, and another p-type well region 10 are formed respectively by selective ion implantations of n-type and p-type impurities.
In such a configuration, as the transfer electrode 19 is formed after the formation of the readout gate region (ROG) 30 and the impurity diffusion layer 5, a positional offset and the like made when forming the opening of the transfer electrode 19 cause a distance X between the readout gate region (ROG) 30 and an edge of the opening of the transfer electrode in the direction along the surface of the substrate.
In the solid-state image capturing apparatus 200, the distance X is measured, for example, for each wafer, and the ion implantation angle of boron for forming the p-type diffusion layer 9 of the surface of the sensor region 5 is adjusted such that a region between the readout gate region (ROG) 30 and the p-type diffusion layer 9 has an appropriate concentration in accordance with the distance X.    Reference 1: Japanese Laid-Open Publication No. 2005-159062